Drainage control



Jan. 2, 1934. w. PRUNEAU 1,941,573

DRAINAGE CONTROL Filed Oct. 31, 1932 Patentd Jan. 2, 1934 UNITED STATES PATENT OFFICE Application October 31, 1932, Serial No. 640,420, and in Canada March 30, 1932 5 Claims. (01. 23656) The present invention pertains to a novel drainage control for steam systems, such as the internally heated cylinders of a paper making machine.

In such machines it is necessary ,to maintain a constant temperature within the cylinders. Accordingly, the air and condensate must be drained therefrom, but it is also desirable, in the interest of economy, to avoid draining steam also. The principal object of the invention is to provide an apparatus for draining the air and condensate without exhausting useful steam.

Accordingly, there is provided a tank into which air and condensate are drained by the action of a suction .line connected to the tank. A by-pass also extends fromthe tank to the suction line. When the system commences to draw steam into the by-pass, a heat-sensitive member therein closes a valve in the suction lime. Thereupon, water accumulates in the tank until it overfiows into the by-pass, cooling the heat-sensitive member and again opening the valve in the suction line to permit normal functioning.

The drainage apparatus is also useful in ;analogous steam systems.

The invention is fully disclosed by way of example in the follovving description and in the accompanying drawing in which Figure 1 is an elevation of the control apparatus applied to a paper drier shown diagrammatically;

Figure 2 is an elevation, partly in section, of the diaphragm valve;

Figure 3 is a detail section of the pressure generator for the valve; and

Figure 4 is a detail section of the restriction member.

Reference to these views W111 now be made by use of like characters which are employed to ;designate corresponding parts throughout.

In Figure 1 is shown a series of cylinders or steam rolls 1 between which the pulp is passed to be formed into a sheet. In the present instance, the pulp enters at the left, and the sheet :15 discharged at the right.

Steam is supplied to the interior of the cylinders from a steam line 2 entering a manifold 3 which in turn is connected by individual limes 4 to the respective cylinders, or at least to these Icylinders near the right or discharge end which require higher temperature. An exhaust manifold 5 is connected by similar individual limes 6 to the remaining or discharge ends of the cylinders 1.

The low pressure for inducing exhaust of the cylinders is derived from a pump 7. By means of connected suction pipes 8 and 10, the pump is connected to the bottom of a drainage tank 9, the top of which is in communication with the exhaust manifold 5. Another by-pass pipe 11 go,

extends from the joint 12 between pipes 8 and 10 and is connected into the tank 9 at the normal water level therein as will presently appear.

A diaphragm valve 13 is interposed in the pipe 10 and is controlled by a pressure generator 14 which is shown in detail in Figure 3. The generator is shown and described in the U. S. patent to Copley, No. 1,193,125 of August 1, 1916. It comprises a casing 15 through which the pipe 11 passes and which contains a highly expansible fluid. A tube 16 extends from the casing to the diaphragm valve which is normally held open by a spring 17. The nature of the expansible fluid is such that, when heated by steam flowing through pipe 11, it generates sufiicient pressure in the tube 16 t0 counteract the spring 17 and close the valve 13. On the other hand, when water fiows in pipe 11, the pressure drops, and the spring 17 opens the valve 13.

A hand valve 18 is provided at the upper end of the pipe 11 and connected by a nipple 20*to the tank 9, which completes the fluid communication between the pipe and the tank. A similar hand valve 19 is interposed between the pipe 11 and the joint 12.

The normal water level in the tank 9 is at the nipple 20, as indicated by the line 21. The pipe 11 contains a fitting 22 having a restriction 23 to cause water to accumulate rapidly in the pipe 11 for a purpose which will presently appear. Finally, a filter 24 is inserted in the pipe ahead of the member 22 to avoid clogging of the restriction 23 by solid particles.

With reference to the operation of the device, it will be understood that it is desired to avoid withdrawal of steam from the cylinders 1. Such withdrawal of steam not only is wasteful, but destroys the uniform temperature in the cylinders which is necessary for eficient operatien and the manufacture of a satisfactory product. on the other hand, these latter naquirements are not met if the air and condensate are not withdrawn from the cylinders.

As already explained, the valve 13 is open while water flows in the pipe 11. This condition obviously exists as long as the water level in the tank 9 is above the nipple 20. When this level falls, however, and the pump 7 commences to draw steam through the by-pass pipe 11, the generator 14 develops sufiicient pressure to close the valve 13 as already described. The water drawn into the tank, having no outlet through the pipe 10, rises tothe level of the nippIe 20 and enters the pipe 11. The restriction 23 causes accumulation of water in the pipe section Within the generator, thereby hastening the cooling effect therein and the co-nsequent opening of the valve 13 to restore normal operation. In short, the drainage system is immediately blocked as soon as it commences to draw steam and remains in this condition until proper and normal funetioning is resumed.

If desired, another drainage unit 25 may be supplied for certain of the cylinders 1 and Operated by the same pump 7. This unit m'ay serve the cylinders at the left or entrance end which requires less heat than the discharge end. In such case, the intake manifold 26 may be connected to the top of the tank 9 to take the steam withdrawn from the botter cylinders.

The manifold is connected by limes 27 to the respective cylinders which have their exhaust ends connected by fines 28 to the exhaust manifold 29, the latter being connected to the top of the 253 drainage tank 30 of the unit 25.

Although a specific embodiment of the invention has been illustrated and described, it will be understood that various alterations in the details of construction may be made without departing from the scope of the invention as indicated by the appended claims.

What I claim is:- 1. A drainage control comprising a tank adapted for connection to the member to be drained, a drain pipe extending from the bottom of said tank, a by-pass extending from said tank into said pipe, a normally open valve in said pipe, and steam-actuated means at said by-pass for closing said valve, said by-pass having a restric- -tion between said means and said pipe and at the normal water level of said tank.

2. A drainage control comprising a tank adapted for connection to the member to be drained, a drain pipe extending from the bottom of said tank, a pump connected to said pipe, a by-pass extending from said tank into said pipe, a normally open valve in said pipe, and steam-actuated means at said by-pass for closing said valve, said by-pass having et restriction between said means and said pipe and at the normal Water level of said tank.

3. A drainage control comprising a tank adapted for connection to the member to be drained, a drain pipe extending from the bottom of said tank, a by-pass extending from said tank into said pipe, a normally open diaphragm valve in said pipe, and a pressure generator at said by-pass adapted to close said valve by fiow of steam in said by-pass, said by-pass having a restriction between said generator and said pipe and at the normal water level of said tank.

4. A drainage control for paper making machines comprising a tank adapted for connection to the machine to be drained, a drain pipe extending from the bottom of said tank, a by-pass extending from said tank into said pipe, a normally open valve in said pipe between said tank and the union of the by-pass with said drain pipe, and steam-actuated means at said by-pass for closing said valve.

5. A drainage control for paper making machines comprising a tank adapted for connection to the machine to be drained, a drain pipe extending from the bottom of said tank, a by-pass extending from said tank into said pipe, 2, normally open valve in said pipe between said tank and 11J the union of the by-pass with said drain pipe, and steam-actuated means at said by-pass for closing said valve, and a pump connected to said pipe beyond said union.

WILFRID PRUNEA. 

